The Anteromedial Portal for Anterior Cruciate Ligament Reconstruction

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Chapter 19 The Anteromedial Portal for Anterior Cruciate Ligament Reconstruction

Manfred Bernard, Stavros Ristanis, Vassilis Chouliaras, Hans Paessler, Anastasios Georgoulis

Introduction

The correct placement of the femoral tunnel is very essential for the success of the anterior cruciate ligament (ACL) reconstruction. The transtibial drilling of the femoral tunnel has been very much popularized because of its simplicity and good visualization. However, there is evidence that drilling the femoral tunnel through the tibial tunnel can result in a nonanatomical placement of the graft in the femur.1

In the past, drilling the femoral tunnel more laterally at the medial surface of the lateral femoral condyle (LFC) (2 or 10 o’clock) has been proposed for better functional results, especially to avoid not only the anterior drawer but also the pathological rotation of the tibia.2–4 Recently it was shown the tension curve of grafts in the 9-o’clock position is similar to the characteristic pattern of the normal ACL’s tension curve.5 To reach this position (centered at 2 or 10 o’clock with the lowest point near 9 or 3 o’clock), the anteromedial portal is essential.

Thus, the anteromedial portal has become more and more attractive lately, and a large number of orthopaedic surgeons prefer this portal.6–12

Advantages

The advantages of this technique are as follows:

1 Easy manipulation of the instruments to drill the tunnel in any position at the medial side of the LFC without considering the placement of the tibial tunnel.
2 The femoral and tibial tunnels are drilled separately. Thus, one can choose the desired placement of the femoral tunnel without considering the placement of the tibial tunnel.
3 There is no risk of enlarging the tibial tunnel posteriorly, which can lead to poor fitting and stabilization of the graft in the tunnel.
4 By using bone–patellar tendon–bone (BPTB) graft, there is not any divergence when placing the interference screw.
5 In two-bundle ACL reconstruction, it is easier to choose the two entry points.
6 The drilling can be performed with the knee flexed to 120 degrees. In this position the 10-o’lock and also the 9-o’clock position can easily be reached without the risk of a blow-out fracture of the dorsal corticalis of the femoral condyle.
7 The correct rotation of the graft insertion toward the long femur axis (important to restore the anteromedial and posterolateral bundle using BPTB graft) is easily found because it is parallel to the tibia plateau in the 120-degree flexion position.

Technique

The technique is as follows:

1 Place the anterolateral portal for the arthroscope 2 to 3 cm higher than the tibial plateau between the lateral distal border of the patella and the LFC. Place the anteromedial portal 1 cm higher than the tibial plateau and very close to the medial border of the patellar tendon.
2 Resect the ligamentum mucosum and, if needed, pieces of infrapatellar fat for better visualization. In 90 degrees of flexion, débride the posterior surface of the medial side of the LFC from soft tissues. The posterior margin of the notch must be clearly identified to ensure an over-the-top position. This identification is very important to place the femoral tunnel as far posteriorly as desired. Introduce a femoral guide (6 mm offset for an 8-mm hamstring graft or 7 mm offset for a 10-mm BPTB graft) through the medial portal.
3 Slowly flex the knee to 120 degrees, and check for good visualization. Sometimes, higher fluid pressure is demanded, or parts of the fat pad have to be removed to have good visualization of the femoral footprint of the ACL. The center of the femoral tunnel is the center of the ACL footprint at 10 o’clock in the left knee and 2 o’clock in the right knee. Drill a 2.5-mm guidewire through the LFC with the knee in 120 degrees of flexion; the drill exits from the skin at the lateral side of the femur. In this position (120 degrees of flexion), the drill should be aligned parallel to the tibial plateau. Thus, a dorsal blow-out fracture is surely avoided.
4 If you are certain that the guidewire is in the correct position, overdrill the guidewire with a reamer in the chosen depth (8-mm diameter and 35-mm depth for a hamstring graft stabilized by Endobutton or 10-mm diameter and 25-mm depth for a BPTB graft).
5 If you are not sure about the correct position, the placement of the guidewire should be controlled fluoroscopically (recommended for all arthroscopic procedures) as follows:
Change the drilling machine and fix it at that end of the wire that exits through the skin. Withdraw the Kirschner wire (K wire) until its inner end is flushed with the bone level of the LFC. Now the ending of the K wire marks the estimated center of ACL insertion (Fig. 19-1).
Under fluoroscopic control in strictly lateral projection, superimpose both femoral condyles on the monitor. Measure the position of the end of the K wire using the quadrant method (Figs. 19-2 and 19-3).13
It is not necessary to perform an additional fluoroscopic tunnel view because the quadrant method determines the position of the end of the K wire in the anteroposterior direction as well (Fig. 19-4).
Overdrill the K wire if its position is correct; if not, replace the K wire, and repeat the fluoroscopy.
6 Remove a small piece of the entry of the femoral tunnel, where the screw has to be inserted by BPTB graft.
7 Drill the tibial tunnel in 90 degrees of flexion. The entry point is selected close to the anterior border of the medial collateral ligament (MCL). The center of the tibial tunnel in the intraarticular space is slightly medial to the center of the intercondylar region on a line joining the inner edge of the anterior horn of the lateral meniscus and the medial tibial spine. With the knee joint in hyperextension and dorsal drawer position, we check that this point is at least 5 mm dorsal from the roof of the intercondylar notch to avoid an impingement of the graft.
8 Introduce the tibial guide, and insert a guidewire at an angle of 60 degrees to the tibial plateau. Overdrill the guide with the desired reamer, and check for possible impingement.
9 With eyelet K wire, pull a suture to the lateral side of the femur. Pull the suture from the tibial tunnel until the medial side of the tibia is reached.
10 Pull the graft to the desired position, using this suture. Sometimes it is necessary to extend or flex the knee joint to facilitate passing the graft through the tibial and femoral tunnels.
11 Using the BPTB graft, rotate the femoral bone block in the tunnel such that the anatomical angle between the long axis of the insertion area and the long axis of the femur is restored. This is reached by adjusting the corticalis of the bone block parallel to the tibial plateau in 120 degrees of knee flexion. In this position the anatomy of the anteromedial and posterolateral bundle is reconstructed.
12 Performing the double-bundle technique; the line between both femoral drill holes should be parallel to the tibial plateau in 120 degrees of knee flexion to restore the correct course of the bundles. This orientation is only achieved using the anteromedial portal (Fig. 19-5).
13 Using the BPTB graft, insert a screw guide parallel to the bone plug through the small widening of the femoral tunnel. Flex the knee joint to 120 degrees, and insert the screw under visualization.
14 Fix the graft at the tibia in about 25 to 30 degrees of flexion.
image

Fig. 19-1 Withdraw the K wire (A) until its end is flush with the wall of the lateral condyle (B).

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Fig. 19-2 Fluoroscopic control in lateral projection (A). The end of the K wire (red circle) marks the estimated center of the insertion (B).

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Fig. 19-3 Quadrant method: taking a strictly lateral radiograph, superimposing both condyles, quartering the sagittal diameter, and quartering the notch height. The center of the anterior cruciate ligament (ACL) insertion is located in the distal corner of the most superoposterior quadrant (arrow).

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Fig. 19-4 Example of K wire positioning in true lateral projection (A) and in Frick’s projection (B). The yellow arrows demonstrate the correlation of the endings of the K wires (black points) in both projections if they are even with the bony surface of the condyle. The position in craniocaudal direction in the lateral view corresponds to the clockwise position in the tunnel view. For instance, a positioning at 25% of B (height of the notch) in the lateral view leads to the 1:30 clock position in the anteroposterior view (left knee). A drill hole that is positioned at 0% of B in the lateral projection would be in the high-noon position in Frick’s projection.

image image

Fig. 19-5 In 120 degrees of knee flexion, the corticalis of bone block should be adjusted toward and parallel to the tibial plateau. Because of the tibial slope, an angle of 25 degrees results between the long axis of the insertion area and the axis of the femur (A). This corresponds to the anatomical inclination angle of 26 degrees between both axes (B). Restoring this correct inclination angle is important to reconstruct the course of the anteromedial and posterolateral bundle. Similar conditions are valid when performing the double-bundle technique. In this case the line between both femoral drill holes should be parallel to the tibial plateau in 120 degrees of knee flexion. This orientation is only achieved using the anteromedial portal.

Possible Complications

Possible complications include the following:

1 Risk of breaking the posterior femoral cortex if the knee is not in 120 degrees of flexion.
2 Poor visualization by inserting an interference screw in 120 degrees of flexion. In this case, insert the screw in 90 degrees of flexion until the tip is at the femoral tunnel, and then bend the knee joint in 120 degrees of flexion, and insert the screw in this position.

References

1 Arnold MP, Kooloos J, van Kampen A. Single-incision technique misses the anatomical femoral anterior cruciate ligament insertion: a cadaver study. Knee Surg Sports Traumatol Arthrosc. 2001;9:194-199.

2 Georgoulis A, Papadonikolakis A, Papageorgiou CD, et al. Three-dimensional tibiofemoral kinematics of the anterior cruciate ligament-deficient and reconstructed knee during walking. Am J Sports Med. 2003;31:76-79.

3 Ristanis S, Giakas G, Papageorgiou CD, et al. The effects of anterior cruciate ligament reconstruction on tibial rotation during pivoting after descending stairs. Knee Surg Sports Traumatol Arthrosc. 2003;11:360-365.

4 Yagi M, Wong E, Kanamori A, et al. Biomechanical analysis of an anatomic anterior cruciate ligament reconstruction. Am J Sports Med. 2002;30:660-666.

5 Arnold MP, Verdonschot N, van Kampen A. ACL graft can replicate the normal ligament’s tension curve. Knee Surg Sports Traumatol Arthrosc. 2005;13:625-631.

6 Paessler HH. New techniques in knee surgery. 2003. Darmstadt

7 Scranton PE, Pinczewski L, Auld MK, et al. Outpatient endoscopic quadruple hamstring anterior cruciate ligament reconstruction. Oper Tech Orthop. 1996;6:177-180.

8 Giron F, Buzzi R, Aglietti P. Femoral tunnel position in anterior cruciate ligament reconstruction using three techniques. A cadaver study. Arthroscopy. 1999;15:750-756.

9 Hertel P, Behrend H, Cierpinski T, et al. ACL reconstruction using bone-patellar tendon-bone press-fit fixation: 10-year clinical results. Knee Surg Sports Traumatol Arthrosc. 2005;13:248-255.

10 Chhabra A, Kline AJ, Nilles KM, Harner CD. Tunnel expansion after anterior cruciate ligament reconstruction with autogenous hamstrings: a comparison of the medial portal and transtibial techniques. Arthro-scopy. 2006;22:1107-1112.

11 Bellier G, Christel P, Colombet P, et al. Double-stranded hamstring graft for anterior cruciate ligament reconstruction. Arthroscopy. 2004;20:890-894.

12 Morgan CD, Stein DA, Leitman EH, Kalman VR. Anatomic tibial graft fixation using a retrograde bio-interference screw for endoscopic anterior cruciate ligament reconstruction. Arthroscopy. 2002;18(7):E38.

13 Bernard M, Hertel P, Hornung H, et al. Femoral insertion of the ACL. Radiographic quadrant method. Am J Knee Surg. 1997;10:14-22.

Suggested Readings

Galla M, Uffmann J, Lobenhoffer P. Femoral fixation of hamstring tendon autografts using the TransFix device with additional bone grafting in an anteromedial portal technique. Arch Orthop Trauma Surg. 2004;124:281-284.

Georgoulis AD, Papageorgiou CD, Makris CA, et al. Anterior cruciate ligament reconstruction with the press-fit technique: 2–5 years follow-up of 42 patients. Acta Orthop Scand Suppl. 1997;275:42-45.

Georgoulis AD, Tokis A, Bernard M, et al. The anteromedial portal for drilling of the femoral tunnel for ACL reconstruction. Tech Orthop. 2005;20:228-229.

Gobbi A, Mahajan S, Tuy B, et al. Hamstring graft tibial fixation: biomechanical properties of different linkage systems. Knee Surg Sports Traumatol Arthrosc. 2002;10:330-334.

Hantes ME, Dailiana Z, Zachos VC, et al. Anterior cruciate ligament reconstruction using the Bio-TransFix femoral fixation device and anteromedial portal technique. Knee Surg Sports Traumatol Arthrosc. 2006;14:497-501.

Lobenhoffer P, Bernard M, Agneskirchner J. Qualitätssicherung in der Kreuzbandchirurgie. Arthroskopie. 2003;16:202-208.

Pässler 2004 Pässler HH, Höher J. Intraoperative Qualitätskontrolle bei der Bohrkanalplatzierung zum vorderen Kreuzbandersatz Unfallchirurg. 2004;107:263-272.

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